An apparatus having a wireless part instead of a wire part has recently become widespread. For example, a personal computer is connected to a printer by radio. For this radio connection, an apparatus employing a radio communication standard called Bluetooth has become widespread. Bluetooth is defined by a standardization group called the Bluetooth Special Interest Group (Bluetooth SIG). Bluetooth is normalized for the purpose of interconnecting a notebook-sized personal computer, a personal digital assistant (PDA), and a cellular phone without using a cable to communicate sound or data.
A cellular phone or a cordless phone connectable by Bluetooth is also developed as an option. Such a phone has both a Bluetooth system and a telephone system. A radio communication apparatus can thus be realized which includes a cellular phone or a cordless phone having a Bluetooth communication function and can perform the radio communication. A Bluetooth radio unit (BT radio unit) and a phone radio unit (CDL radio unit) are individually disposed for responding to radio signals with different modes in the prior art, and this structure leads to the enlargement of the apparatus and the cost increase.